Mail Guard

Mail Guard checks visible sender information, text and links in emails you open in desktop Gmail. It helps you spot inconsistencies before you follow a link. Main features - Compares displayed link text with the destination domain and checks nearby requests involving account actions or passwords. - Groups repeated findings and explains the reasons alongside the URL found in the email. Where relevant, you can jump to the original sender or link and highlight its location. - Shows additional information when the displayed sender name or address appears inconsistent with the sender address domain. - When you open a message’s sender details in Gmail, compares available sending, forwarding and reported signing domains with the sender domain. It never opens those details automatically. - Shows a confirmation dialog before opening links that carry warnings in Gmail. - Checks pasted email content or headers and local .eml or .txt files in Settings, up to 5 MB per input. - Offers 11 interface languages, an option to pause automatic Gmail checks and controls for additional information. Local processing and privacy Analysis runs on your device, without AI or remote analysis services. Email content and results are not saved or uploaded; only preferences are stored. Observed Gmail sender details stay temporarily in memory for the corresponding displayed message and are cleared when the message or view changes, or checks are disabled. Analysis does not visit linked websites. Opening a link yourself causes normal browser network activity. Scope and limitations Sender or domain differences alone are informational, not proof of impersonation. Legitimate forwarding can change domains. The extension compares reported information but does not independently verify SPF, DKIM, DMARC or ARC. Available Gmail details depend on the language, layout and whether you have opened them. Missing information is not treated as an authentication failure. Images, QR codes, attachments and destination pages are not inspected. Displayed URLs come from the email and are not verified final destinations after redirects. Right-click menus, dragging links and opening copied URLs elsewhere are not fully controlled. Checks can flag legitimate messages or miss threats. The absence of a warning does not guarantee that a message is safe or its sender is genuine. Source code: https://github.com/neneneru/mail-guard Privacy policy: https://github.com/neneneru/mail-guard/blob/main/PRIVACY.md